Dopamine

Using an imagining technique known as PET, scientists at Brookhaven National Laboratory discovered an aging-related decline in dopamine D2 receptors. This receptor loss makes dopamine less available to brain cells. The exciting part of this finding was a newly discovered connection between dopamine and glucose metabolism. Lower dopamine activity apparently leads to a decrease in neural glucose metabolism, which results in less energy production in the brain. This decrease in energy output was found to be regional, affecting the frontal lobes and the anterior cingulate gyrus.

In an attempt to formulate a working hypothesis of basal-ganglia functions, arguments are considered suggesting that the basal ganglia are involved in a process of response selection, i.e., in the facilitation of "wanted" and in the suppression of "unwanted" behavior. The meso-accumbal dopamine-system is considered to mediate natural and drug-induced reward and sensitization.